Okay, let me just repeat the pronouncement that I made in the subject-line: I am about to mention at least one HUGE SPOILER about the third Harry Potter movie. If you don't want to hear about the plot and the ending, STOP READING NOW. You've been warned. ' ' ' ' ' ' ' ' If you're still reading it means you don't mind spoilers. ' ' ' ' ' ' ' I'm not kidding! ' ' ' ' ' ' ' ' Okay then. You were warned! ' ' ' ' ' Those of who you have sufficiently long lifespans to be able to read this post over on the TV board will know that I am irritated by non-logical time-travel plots. I can't ever remember seeing a film or TV time travel story that made perfect logical sense before (with the possible exception of cases where they entirely circumvent the past/present interaction aspect of time travel, for example in Time Bandits). So I was perfectly astonished to discover that a Harry Potter film - a Harry Potter film for God's sake - actually managed a time-travel plot with no logical contradictions. Every single thing that the time travellers did which in any way affected their earlier selves we also saw happening the first time round - though, of course, at the time, we didn't fully realise the significance. Amazing. My question is: if Harry Potter can get this right, why can't anyone else?